Plastifying apparatus

ABSTRACT

A plastifying apparatus is disclosed. A rotatable roller has arranged angularly spaced with reference to its periphery a plurality of gap-forming elements each of which defines with the periphery a wedge-shaped gap which tapers in direction of rotation of the roller. Feed means feeds material to be plastified into the first one of the gaps for successive movement through this and the following gaps as the roller rotates, whereby the material undergoes successive plastification steps.

mite tates atent (Collin [54] PLASTIFYING APPARATUS [72] Inventor:Heinrich Collin, Munich, Germany [73] Assignee: Krauss-MaffeiAktiengesellschait, Munich, Germany [22] Filed: March 12, 1970 [21]Appl. No.: 18,903

[30] Foreign Application Priority Data March 13, 1969 Germany ..P 19 12779.8

[52] US. Cl ..425/224, 264/212 [51] Int. Cl. ..B29d 7/02 [58] Field ofSearch "1 8/9, l0, l5, 2 C; 264/349, 264/212, 216, 175; 425/224 [56]References Cited UNITED STATES PATENTS 3,158,670 11/1964 Camras..1s/15Rx' 1 1 Dec.12,1972

2,014,937 9/1935 Kratz et al. .Q.....264/212 2,546,342 3/1951 Jurgensenet al. ..264/2l2 X 3,098,262 7/1963 Wisotzky ..264/2l2 UX PrimaryExaminer-J. Spencer Overholser Assistant Examiner-Norman E. LehrerAtt0rneyMichael S. Striker [5 7 ABSTRACT A plastifying apparatus isdisclosed. A rotatable roller has arranged angularly spaced withreference to its periphery a plurality of gap-forming elements each ofwhich defines with the periphery a wedge-shaped gap which tapers indirection of rotation of the roller. Feed means feeds material to beplastified into the first one of the gaps for successive movementthrough this and the following gaps as the roller rotates, whereby thematerial undergoes successive plastification steps.

20 Claims, 7 Drawing Figures PATENIEU DEC 12 1912 SHEET 1 OF 5 INVENTOR[lawman 066! h ma Shh ATTORNEY FIG. 2

INVENTOR Hewuc I Crab/u adedJv ATTORNEY PATENTEnuzc 12 972 3.705.778

sum 3 or s INVENTOR UN-I60 6 66/ N 22 0/5- sh-a ATTORNEY INVENTOR I'm/meCon/41 BY 4M ATTORNEY PATENTEDDEB 12 I972 3' 705. 778

SHEET 5 0r 5 INVENTOR l! C064! ATTORNEY PLASTIFYING APPARATUS BACKGROUNDOF THE INVENTION The present invention relates generally to theplastification of materials, and more particularly to an apparatus forplastification of materials. Still more specifically the inventionrelates to an apparatus for plastifying tenacious materials,particularly masses of synthetic plastics.

An apparatus for plastifying tenacious masses is known from German Pat.No. 1,256,401. Here the masses are supplied by means of a feed screwonto one end of a rotatable roller. Means is provided which definestapered gaps with the periphery of the roller and the mass to beplastified is repeatedly passed through these tapered gaps and advancedhelically with reference to the axis of rotation of the roller. At theother end of the roller an outlet is provided at which the mass leaves.The material or mass to be plastified is supplied in form of a narrowribbon so that the width of the roller is not properly utilized. It isnot possible with this construction to produce foils or sheets ofmaterial, particularly in view of the fact that the rollers utilized inthe aforementioned patent are self-adjusting and not stationarilymounted.

It is, however, of particular interest that foils be capable ofproduction in accordance with this general approach, because heretoforethe production of foilsespecially those of polyvinylchlorideis generallycarried out on multiple-roller calenders which are expensive in theirinitial investment cost and rather large so that they requiresignificant space availability. Evidently, high investment expenses andlarge space requirements are disadvantages which have been sought to beovercome heretofore by utilizing tworoller calendars in which apredetermined quantity of synthetic plastic material is plastified byrepeatedly passing through. the gap defined between the two rollers soas to be convertedinto a foil. However, this approach has not been foundpractical because even calendars constructed in this manner areexpensive, aside from the fact that the production of foils in thismanner is possible only discontinuously because, as just pointed out,the material to be plastified must be supplied in batches.

SUMMARY OF THE INVENTION It is, accordingly, an object of the presentinvention to overcome the aforementioned disadvantages.

More particularly it is an object of the present invention to provide anapparatus for plastifying materials and converting the plastifiedmaterials into foils or sheets, which not only requires smallerinvestment expenses but which also permits a continuous production.

In pursuance of the above objects, and others which will become apparenthereafter, one feature of the invention resides in an apparatus whichcomprises a rotatable roller having a periphery and a plurality ofstationary gap-forming elements arranged angularly spaced about theperiphery and defining with the same respective wedge-shaped gaps whichtaper in direction of rotation of the roller. Feed means is provided forfeeding material to be plastified into a first one of the gaps forsuccessive movement of such material through all the gaps in response torotation of the roller.

Utilization of the novel apparatus according to the present inventionmakes it possible to produce foil continuously and of excellent qualityby means of a single rotatable roller, and to do so under fullutilization of the axial length of the roller. It is an important aspectof the invention that the mass being plastified passes successivelythrough the respective gaps, and that the plastification is completedwhen the mass has passed once through each of the gaps, so that a secondpass through any of the gaps is not necessary.

By mounting the roller stationarily-except for its ability to rotate-thefoil produced with the arrangement according to the present inventioncan be made of a predetermined precise thickness because the position ofthe roller in space does not vary so that it is a simple matter toprovide for exact adjustment of the width of the gaps which isdeterminative-particularly the ultimate or terminal gapof the thicknessof the finished foil. By arranging the gaps so that they are positioneddownstream of one another, with each gap receiving the foil from therespective preceding gap, certain advantages with respect to operationand economy are obtained. A change in the mass between any twosuccessive gaps-which follow closely on one another and in which themass undergoes kneading or plastification-is precluded and the availableheat is utilized to maximum extent because cooling of the surface of thematerial as it moves from one gap to the next successive gap byradiation of heat and heat exchange with the ambient air issubstantially avoided.

The configuration of the gaps is important with respect to the period oftime for which the mass is in contact with the wall of the gap-formingelement, and at the core or center of the pocket of material whichundergoes at any given moment plastification in any one of the gaps, theso-called dwell time. This dwell time is important particularly inworking of materials whose characteristics vary with time, for instancedeterioration of polyvinyl chloride during long dwell time at highworking temperatures. This strictly limited dwell time is achieved bythe particular configuration of the gaps which, according to anadvantageous embodiment of the invention, are bounded between thecircumference of the roller and straight surfaces on the gap-formingelements which define with the roller circumference a tangential angleof between 0 and approximately 45. Optimum-that is shortest-dwell timeis obtained if the angle is between substantially l5 and 30. Thisminimum dwell time which is required for sufficient homogenization of aplastic mass, can be obtained by utilizing a requisite number ofgap-forming elements in conjunction with a roller having the necessarydiameter of corresponding size.

In accordance with a further advantageous feature of the invention thegap-forming elements may be united-or at least some of them may beunited-in form of a single member. Thus, at least two and advantageouslybetween four and six of these gap-forming elements may be united in asingle member provided with grooves whose inner boundary surfacesconstitute the surfaces which define with the circumference of theroller the respective gaps. This provides for a very simple constructionand eliminates any necessity for individually mounting, adjusting andheating the gapforming elements. It is particularly advantageous thatwith this construction only a single member need be adjusted forpermitting a variation in the configuration or width of severaldifferent successive gaps. Clearly, such member can be mounted so thatthe width of all of the gaps can be varied simultaneously, or that forinstance only the width of the ultimate gap can be varied. Of course,the ultimate or terminal gap is the most important because its widthdefines the thickness of the foil which issues from it. Also, it is ofcourse advantageous that with this type of construction a single heatingunit can be provided for heating the member instead of requiringindividual heating units for the individual gap-forming members.Finally, such a member can be readily mounted and can accordingly beconnected with and disconnected from the apparatus according to thepresent invention in a most simple manner.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction, together withadditional objects and advantages thereof, will be best understood fromthe following description of specific embodiments when read inconnection with the accompanying drawmg.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a diagrammatic side viewillustrating an apparatus according to the present invention whichutilizes individual gap-forming elements;

FIG. 2 is a fragmentary section, on an enlarged scale, illustrating afurther embodiment of the invention in a section normal to the axis ofrotation of the roller;

FIG. 3 is a view similar to FIG. 2, on a smaller scale, illustrating afurther embodiment;

FIG. 4 is a diagrammatic view analogous to the embodiment of FIG. 2 butillustrating one possible adjusting means for adjusting the gap width;

FIG. 5 is a fragmentary view analogous to FIG. 4 butt illustrating afurther possibile adjusting means for ad justing the gap width;

FIG. 6 is a diagrammatic end view illustrating a further embodiment ofthe invention; and

FIG. 7 is a fragmentary sectional view taken in direction normal to theaxis of rotation of the roller and illustrating a further adjustingdevice.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing firstly theembodiment illustrated in FIG. ll it will be seen that reference numeral1 identifies a roller rotatable about its axis but otherwisestationarily mounted. The circumference or periphery of this rollercooperates with a plurality of gap-forming elements 2-7 and defines withthe same a corresponding plurality of wedge-shaped gaps 3-13 each ofwhich tapers in the direction of rotation 23 of the roller 1. Roller lis mounted in stationary bearings by means of its shafts or pins 14, andeach of the elements 2-7 is pivotable about a stationary shaft 16. Abolt 17 and nut 1% is provided in conjunction with each of the elements2-7, being arranged between a respective stationary support 20 and thefreely tiltable or pivotable portion of the respective element 2-7, asillustrated. Heating channel 23 is provided in the elements 2-7 throughwhich a heating medium may flow, or which may accommodate heating wiresor the like. Of course, it may be generally said that the channels 21are heatexchange channels, because it is conceivable that under certaincircumstances heat exchange in general may be desirable, that is that acooling fluid rather than a heating fluid, or both in alternatingrelationship, are to pass through these channels.

Each of the elements 2-7 is provided with a surface 27 which is planarand which can be positioned so as to define a predetermined angle withrespect to the tangent of the periphery of the roller 1. According toFIG. 1 this angle is approximately 15 but it may vary between 0 and 45and is at its optimum when it is between substantially 15 and 30.

The material to be plastified, for instance synthetic plastic granulate,agglommerate or melt, is introduced into the first gap 8 in thedirection of the arrow 22 by any suitable feed means, for instance achute C (see FIG. 6). The roller 1 turns in the direction of the arrow23 and the material to be plastified, hereafter identified as thegranulate for the sake of convenience, undergoes kneading in the firstgap. The heating which occurs during this kneading process, inconjunction with the heat supplied through the heating channels 21,initiates the plastification of the material. At the same time thematerial undergoes excellent admixture and homogenization and thenissues at 19 from the narrowest section of the gap 8 in form of alightly plastified skin or sheet which is transported by the continuedrotation of the roller 1 to the next gap 9 wherein the nextplastification step takes place. From the gap 9 the material is againtransported to the gap 10, from there to the gap 11 and from there tothe gap 12. Finally, in the embodiment illustrated in FIG. 1 there is aterminal gap l3, and this receives the material from the gap 12. The gap13 is of particular importance because the width of the narrowestsection 19 of the gap 13 determines the thickness of the sheet or foilwhich issues from the gap 13. This foil may either be removed from theroller ll immediately downstream of the gap 13 as suggested by the arrow24, or only after it passes between the roller 1 and a second roller 26as suggested by the arrow 25, and the second roller 26 may for instancebe constructed as an embossing roller or the like.

Resort to the novel invention, that is the novel method and apparatus asillustrated by way of example in FlG. 1, produces foil continuously fromsufficiently kneaded and admixed plastified mass. One highlyadvantageous aspect of the invention is that with it the entire axiallength or width of the roller 1 can be utilized. Evidently, this resultsin more economical manufacturing conditions.

FIG. 2 shows a further embodiment of the invention. Like referencenumerals identify like elements as in FIG. 1. Here, however, theindividual gap-forming elements 2-7 of FIG. 1 have been replaced with asingle member 30 whose width corresponds to the axial length of theroller 1. It is also provided with the heating channels 22., but inaddition it is provided with four- -or more or fewer-grooves 31-34extending in parallelism with the axis of rotation of the roller 1. Eachof the grooves 34 has the illustrated cross-sectional configuration inthat its downstream portion -as seen with respect to the rotation of theroller 1 as identified by concavely curved surface portion 36. Themaximum depth of the grooves is approximately 3-10 mm and may beidentical in all grooves, or may be decreasing in the direction ofrotation of the roller 1. In the latter case the volumetric content ofeach succeeding gap will of course decrease whereby the median dwelltime of the mass is similarly decreased, a concept which is advantageouswith respect to the temperature of the mass and the attendant danger ofdeterioration thereof.

It will be appreciated that the grooves 31-34 replace and have the samepurpose as the gaps 8-13 shown in FIG. ll. However, the grooves 31-34 inFIG. 2 are directly successive and are connected by short shear surfaces37-41 which have a small spacing from the surface of the roller 1 andextend approximately parallel thereto. The length of the shear surfaces37-41 with respect to the rotation of the roller l is approximately 2-10mm; their distance from the surface of the roller 1 decreases indirection from the shear surface 37 to the shear surface M, with thedistance between the roller 1 and the shear surface 41 being one of thedeterminative factors which govern the thickness of the finally producedfoil. However, it is clearly possible to leave the distance of the shearsurfaces 37-41 from the surface of the roller 1 identical if desired. I

The surface portions 35 are of particular importance because the qualityof the foil obtained with the apparatus according to the presentinvention is largely determined by the kneading and mixing process inthe gaps 42 and 43 during rotation of the roller 1 in the direction ofthe arrow 23, and on entry of the mass into the uppermost gap 42, thatis the leading gap. It is necessary that materials which are susceptibleto damage are subjected to a dwell time which is as short as possible,and that overheating and deterioration or decomposition of the mass withformation of bubbles and decolorations is avoided. If the cross-sectionof the grooves 31-34 is that illustrated in FIG. 2, it has been foundthat a positive angle a, between the respective surface portion 35 andthe tangent to the roller periphery is of advantage, and the angle (1should be in the region between 0 and 40. An angle a, on the orderbetween approximately and is particularly advantageous because despitethe succession of several of the gaps it reduces to a minimum anyconditions of overheating, particularly also in the case of soft andhard polyvinyl chloride.

In the embodiment of FIG. 3 the member as takes the place of the member39 in FIG. 2. Reference numeral identifies the heat-exchange conduits,whereas reference numerals 47, 48 and 49 identify the gap-forminggrooves. The gap-forming surfaces 56 converge upwardly analogous to FIG.2 into concavely curved surface portions 51, whereas the downstreamportions of the surfaces 50 are significantly shortened-with respect tothe configuration shown in FIG. 2-in order to obtain a further concavelycurved surface portion 52 which terminates the grooves M49 at an angleon the order of between 90 and ISO, preferably less than approximatelyl35, with reference to the upwardly directed tangent to the rollersurface. The radius r, of the curved surface portion 52 is smaller thanthe radius r, of the curved surface portion 51; in

fact, it is approximately one third to two thirds of the radius r,. Thepurpose of this is to achieve a further reduction in the dwell time ofthe material at the surface portion and in the interior of therespective gap, as well as to facilitate the flow of the material whichtakes place within the respective gap during the kneading of thematerial. This construction is particularly advantageous for highlydelicate materials, that is materials which are especially susceptibleto damage under the aforementioned conditions. In addition, it will beeseen in FIG. 3 that the depth of the grooves 47-49 decreases in thedirection of rotation of the roller 1 as signified by the arrow 23, withthe groove 49 having the smallest depth. Furthermore, a shear surface 54follows each groove 47-49, that is arranged downstream of the respectivegroove.

FIGS. 4 and 5 illustrate how the respectively terminal gap can beadjusted. In FIG. 4 this terminal gap which, as has already been pointedout before, is of importance for the thickness and also for the surfacequality of the foil produced-is identified with reference numeral 67.The lower portion 57 of the member 55-which is again provided with theheatexchange channels or conduits 56is formed with a slot 58 whose widthis adjustable by means of a screw 59. A further screw 59a is shown inbroken lines and suggests a further possibility for obtaining thedesired effect. Reference numeral 69 identifies the shear surface at thedownstream end of the gap 67.

In the embodiment of FIG. 5 a wedge-shaped member 61 is pressed into aslot with non-parallel side faces by means of a screw 62 which in turnis mounted in a member 64 which is connected with the member 63replacing the member 55 of the embodiment in FIG. 4. The terminal gap ishere identified with reference numeral 68 and the associated shearsurface with reference numeral 70. With the constructions according toFIGS. 4 and 5 the width of the respective terminal gap 67 in FIG. 4 and68 in FIG. 5, and the distance between the roller surface and therespectively associated shear surface 69 or 70 (associated with therespective terminal gap) can be varied in a simple and effective manner.

In the embodiment illustrated in FIG. 6 like reference numerals againidentify like elements. I-Iere,

- however, there are provided two members and 76 located at oppositesides of the roller 1. With this construction the pressures which actupon the roller 1 as a result of the hydrodynamic pressure increases inthe gaps 77 at least in part negate one another so that there is a muchsmaller bending pressure exerted upon the roller 1 than would normallybe expected from the pressures which develop in the gaps 77 and act uponthe roller 1. The result is a significantly decreased load upon the(non-illustrated) bearings for the roller 1. It is hardly necessary toemphasize that this is highly advantageous in that the avoidance ofbending or flexing of the roller l transversely of its elongation is ofsignificant importance in the production of foils of constant thickness.

Coming now to the embodiment of FIG. 7 it will be seen that this isconcerned with the adjustability of the member 80 which corresponds toone of the previously described members, for instance is analogous toone of the members 75 or 76 of FIG. 6. Such adjustability is of l060l0040i importance because the members-such as the member 8 lihas aplurality of grooves which define with the circumference of the roller lgaps which are fixed with respect to one another-that is with respect totheir position on the member 841-; because of this, and because in someembodiments it is desired that the terminal gap be adjustableseparately, the adjusting arrangements must be capable of affordingadjustment of the member 8llor an analogous memberin several directions.This is accomplished in FIG. 7 by providing the member 8ft, which isagain provided with the heatexchange channels 21, with a mounting on atraverse till by means of a wedge-shaped member 82 which is verticallyshiftable via a screw 83 and thus permits simultaneous adjustment of allgap widths between the member $63 and the circumference of the roller 1.There are further provided additional screws 84 which serve to permitshifting movement of the member 80 in a plane which is in parallelismwith the axis of rotation of the roller 11, so that the gap widths arevaried not identically but differently. The screws 84 and 85 serve toarrest the member 80 with reference to the traverse bl when tightened.The latter is further pivotable about a shaft 556 which is stationaryand extends in parallelism with the axes of rotation of the roller 1.This makes it possible for the member 80 to be tilted towards the rightin FIG. 7 so that access can always be had readily for cleaningpurposes, inspection purposes and for removal if necessary. Such pivotaction is accomplished by means of a worm gear drive 87, 88 when ahandwheel $9 is rotated. The kneading forces in the gaps are resisted bya ram 9ft which is mounted stationarily, for instance by being supportedon the housing of the apparatus.

it is one of the particular advantages of using members such as themember 80, or the analogous members which have been described andillustrated in the preceding embodiments, that aside from the initial orfirst gap into which the material to be plasticized originallypasses-the intrusion of air into the mass undergoing plastificationandmore particularly into the space between the downstream ends of therespective gaps and the upstream ends of the next-following gaps wherethe mass passes in form of a foil over the circumference of the roller,or into the space between the circurnference of the roller and the mass,is avoided. Furthermore, the material leaving the first or initial gap,and in fact the first several gaps, is still only partially plastitiedand therefore has the tendency to move away from the rollercircumference and to curl about the edge of the respective gap-formingelement, thereby very possibly forming at the same time an airinclusionwithin the material. This is avoided with the type of element underdiscussion in the embodiments 2-7, such as the element 8b, where severalof the individual gap-forming elements are united in a single memberbid, or an analogous member. Of course, there is also the advantage thatwith this particular construction the space requirements aresignificantly decreased over those which would prevail if individualgap-forming elements were used as in the embodiment of FIG. 1, so that asignificantly greater number of gaps can be provided as seen withrespect to the circumference of the roller, whereby a greater degree ofadmixture and plastification is achieved. Also, mounting space,measuring space and other space requirements which would be necessary ifthe gap-forming elements were individual as in FIG. l, are avoided.

A further advantage of utilizing the member 80 or an analogous member isthe fact that the kneading processes which take place in the gaps formedbetween this member and the circumference of the roller 1 can be morereadily controlled. While the terminal or final gap is determinative ofthe thickness of the foil produced, the preceding gaps control thekneading steps. With the exception of the initial gap all others betweenthe initial and the terminal gap are completely filled with materialundergoing the kneading process. Only the initial gap requires a certainadjustment with respect to the supply of material to it. Normally theinlet end of the initial gap will face upwardly and the material will beintroduced in downward direction into this initial gap, and it is asimple matter to control the supply of material to it.

in an embodiment such as that shown in FIG. 6 it is of course possiblenot only to use two of the members, such as the members '75 and 76, butalso to use three or more. The number of gaps can be distributed amongthese members, and it is advantageous if there is a total of twelve oreven more such gaps. If two members, such as the members and 76 areprovided, they are arranged to be located oppositely one another. Ifmore than two members are provided they are equi-angularly distributedwith reference to the circumference of the roller ll. In all instancesit is then possible, as already suggested in the discussion of theembodiment of FIG. 6, to so arrange the members that the pressuresoriginating in the respective gaps thereof will negate or at leastsubstantially negate one another to avoid bending stresses upon theroller 1. It is essential in this connection that the terminal or finalgap, from which the finished foil issues, exert upon the roller 1 apressure which is higher than that exerted by the other gaps of the samemember so that floating of the roller in view of the unavoidable bearingplay is avoided and the thickness of the foil can be maintainedconstant. Otherwise, that is if the roller 1 could yield in thebearings, variations in the width of the outlet end of the terminal gapwould result in variations of the thickness of the foil produced.

it will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofconstructions differing from the types described above.

While the invention has been illustrated and described as embodied in anapparatus for plastification of plastifiable materials, it is notintended to be limited to the details shown, since various modificationsand structural changes may be made without departing in any way from thespirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning of the following claims.

lOOlO 0402 What is claimed as new and desired to be protected by LettersPatent is set forth in the appended claims:

11. An apparatus for plastifying of materials, particularly of syntheticplastics, and for making foils from such materials, comprising incombination a roller having a periphery; a plurality of stationaryelements angularly spaced about said roller and having respectivesurfaces spaced from and defining with the periphery of said rollerrespective wedge-shaped gaps which taper in direction of rotation ofsaid roller and which have downstream ends extending with slight spacingin at least substantial parallelism with the axis of said roller, saidgaps including an initial and a terminal gap; heating means associatedwith said stationary elements for heating the same; and feed means forfeeding plastifiable material into the initial one of said gaps over theentire length thereof, for successive movement of such material throughall of said gaps in response to rotation of said roller so that suchmaterial becomes plastified in said gaps by heating by said stationaryelements heated by said heating means associated with said stationaryelements and converted into a foil which is discharged from the terminalone of said gaps.

2. An apparatus as defined in claim 1, said gaps having respectiveupstream and downstream end regions which are each concavely curvedinwardly towards said periphery.

3. An apparatus as defined in claim ll; further comprising adjustingmeans for adjusting the taper of the respective gaps.

An apparatus as defined in claim 1, said plurality of elementscomprising between four and six of said elements.

5. An apparatus as defined in claim 1, said surfaces each being a flatsurface.

6. An apparatus for plastifying of materials, particularly of syntheticplastics, and for making foils from such materials, comprising arotatable roller having a periphery; a plurality of stationary elementssubstantially longitudinally coextensive with said roller angularlyspaced thereabout, at least two of said elements being unitary with oneanother in form of a member having a face directed towards said rollerand provided with a plurality of grooves extending in axial parallelismwith said roller and being bounded by groove surfaces which define withthe periphery of said roller respective wedge-shaped gaps which taper indirection of rotation of the roller and include an initial and aterminal gap; and feed means for feeding material into the initial oneof said gaps over the entire length thereof, for successive movement ofsuch material through and processing in all of said gaps in response torotation of said roller, and for discharge of the processed materialfrom the terminal one of said gaps.

7. An apparatus as defined in claim 5, wherein the respective flatsurface includes with a tangent to the periphery of said roller an angleof between and 45.

8. An apparatus as defined in claim 7, wherein said angle is betweensubstantially 15 and 30.

9. An apparatus as defined in claim 6, said plurality of elementscomprising at least one additional member similar to the first-mentionedmember and being angularly spaced with reference to the latter and tosaid periphery.

ll An apparatus as defined in claim 6, said groove faces including withrespective tangents to said periphery angles of between 0 and 30.

111. An apparatus as defined in claim 10, wherein said angles are on theorder of between 10 and 20.

12. An apparatus as defined in claim 10, said gaps having respectiveupstream and downstream ends, and wherein said upstream ends haveupstream end regions which are concavely curved inwardly towards saidperiphery of said roller.

13. An apparatus as defined in claim 6; further comprising adjustingmeans for adjusting the taper of at least said terminal one of saidgaps.

14. An apparatus as defined in claim 6; further com prising adjustablemounting means mounting said member for tilting movement with referenceto said periphery of said roller.

15. An apparatus as defined in claim 2, wherein said downstream endregions are curved so as to include with a tangent opposite to thedirection of rotation of said roller an included angle of betweensubstantially and 150.

11.6. An apparatus as defined in claim 15, wherein said included angleis below substantially 17. An apparatus as defined in claim 15, whereinsaid upstream end regions are curved on a first radius, and saiddownstream end regions are curved on a smaller second radius.

18. An apparatus as defined in claim 17, wherein said first radius isgreater than said second radius by between one-half and twice the amountof said second radius.

19. An apparatus for plastifying of materials, particularly of syntheticplastics, and for making foils from such materials, comprising arotatable roller having a periphery; a plurality of stationary elementssubstantially longitudinally coextensive with said roller-angularlyspaced thereabout and defining with the periphery of said rollerrespective wedge-shaped gaps which taper in direction of rotation of theroller and which include an initial-and a terminal gap; feed means forfeeding material into the initial one of said gaps over the entirelength thereof, for successive movement of such material through andprocessing in all of said gaps in response to rotation of said roller,and for discharge of the processed material from the terminal one ofsaid gaps; and shear surfaces downstream of the respective gaps andextending with slight spacing in at least substantial parallelism withsaid periphery of said roller.

20. An apparatus as defined in claim 19, said shear surface having indirection of rotation of said roller a length between substantially 2and 10 mm.

1. An apparatus for plastifying of materials, particularly of synthetic plastics, and for making foils from such materials, comprising in combination a roller having a periphery; a plurality of stationary elements angularly spaced about said roller and having respective surfaces spaced from and defining with the periphery of said roller respective wedge-shaped gaps which taper in direction of rotation of said roller and which have downstream ends extending with slight spacing in at least substantial parallelism with the axis of said roller, said gaps including an initial and a terminal gap; heating means associated with said stationary elements for heating the same; and feed means for feeding plastifiable material into the initial one of said gaps over the entire length thereof, for successive movement of such material through all of said gaps in response to rotation of said roller so that such material becomes plastified in said gaps by heating by said stationary elements heated by said heating means associated with said stationary elements and converted into a foil which is discharged from the terminal one of said gaps.
 2. An apparatus as defined in claim 1, said gaps having respective upstream and downstream end regions which are each concavely curved inwardly towards said periphery.
 3. An apparatus as defined in claim 1; further comprising adjusting means for adjusting the taper of the respective gaps.
 4. An apparatus as defined in claim 1, said plurality of elements comprising between four and six of said elements.
 5. An apparatus as defined in claim 1, said surfaces each being a flat surface.
 6. An apparatus for plastifying of materials, particularly of synthetic plastics, and for making foils from such materials, comprising a rotatable roller having a periphery; a plurality of stationary elements substantially longitudinally coextensive with said roller angularly spaced thereabout, at least two of said elements being unitary with one another in form of a member having a face directed towards said roller and provided with a plurality of grooves extending in axial parallelism with said roller and being bounded by groove surfaces which define with the periphery of said roller respective wedge-shaped gaps which taper in direction of rotation of the roller and include an initial and a terminal gap; and feed means for feeding material into the initial one of said gaps over the entire length thereof, for successive movement of such material through and processing in all of said gaps in response to rotation of said roller, and for discharge of the processed material from the terminal one of said gaps.
 7. An apparatus as defined in claim 5, wherein the respective flat surface includes with a tangent to the periphery of said roller an angle of between 0* and 45*.
 8. An apparatus as defined in claim 7, wherein said angle is between substantially 15* and 30*.
 9. An apparatus as defined in claim 6, said plurality of elements comprising at least one additional member similar to the first-mentioned member and being angularly spaced with reference to the latter and to said periphery.
 10. An apparatus as defined in claim 6, said groove faces including with respective tangents to said periphery angles of between 0* and 30*.
 11. An apparatus as defined in claim 10, wherein said angles are on the order of between 10* and 20*.
 12. An apparatus as defined in claim 10, said gaps having respective upstream and downstream ends, and wherein said upstream ends have upstream end regions which are concavely curved inwardly towards said periphery of said roller.
 13. An apparatus as defined in claim 6; further comprising adjusting means for adjusting the taper of at least said terminal one of said gaps.
 14. An apparatus as defined in claim 6; further comprising adjustable mounting means mounting said member for tilting movement with reference to said periphery of said roller.
 15. An apparatus as defined in claim 2, wherein said downstream end regions are curved so as to include with a tangent opposite to the direction of rotation of said roller an included angle of between substantially 90* and 150*.
 16. An apparatus as defined in claim 15, wherein said included angle is below substantially 135*.
 17. An apparatus as defined in claim 15, wherein said upstream end regions are curved on a first radius, and said downstream end regions are curved on a smaller second radius.
 18. An apparatus as defined in claim 17, wherein said first radius is greater than said second radius by between one-half and twice the amount of said second radius.
 19. An apparatus for plastifying of materials, particularly of synthetic plastics, and for making foils from such materials, comprising a rotatable roller having a periphery; a plurality of stationary elements substantially longitudinally coextensive with said roller angularly spaced thereabout and defining with the periphery of said roller respective wedge-shaped gaps which taper in direction of rotation of the roller and which include an initial and a terminal gap; feed means for feeding material into the initial one of said gaps over the entire length thereof, for successive movement of such material through and processing in all of said gaps in response to rotation of said roller, and for discharge of the processed material from the terminal one of said gaps; and shear surfaces downstream of the respective gaps and extending with slight spacing in at least substantial parallelism with said periphery of said roller.
 20. An apparatus as defined in claim 19, said shear surface having in direction of rotation of said roller a length between substantially 2 and 10 mm. 